Sodium azide

Specific investigations: other studies

Administrative data

Endpoint:

mechanistic studies

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

documentation insufficient for assessment

Data source

Reference

Reference Type:

publication

Title:

Unnamed

Year:

1989

Materials and methods

Test guideline

Qualifier:

equivalent or similar to guideline

Guideline:

other: OECD Guideline 471

Deviations:

yes

Remarks:

unsuitable metabolic activation system, unsuitable S. typhimurium strain

GLP compliance:

no

Type of method:

in vitro

Endpoint addressed:

genetic toxicity

Test material

Test material information

Constituent 1

Reference substance name:

Sodium azide

EC Number:

247-852-1

EC Name:

Sodium azide

Cas Number:

26628-22-8

Molecular formula:

N3Na

IUPAC Name:

sodium azide

Applicant's summary and conclusion

Executive summary:

Sodium azide is unique among mutagens. It is highly mutagenic in many plant and bacterial species but marginally mutagenic in mammalian cells. A possible explanation for this difference in mutagenic efficiency may lie in the inability of mammalian cells to convert azide to the putative ultimate mutagen.

Normal human fibroblasts and Chinese hamster cells or cell-free extracts from these cell lines were treated with azide and the sonicates tested for mutagenicity in Salmonella strain TA1530. Without removal of excess sodium azide, the cell homogenates exhibited a clear positive effect, with 2-4 fold increase in mutation rate. After removal of sodium azide by acid treatment, the number of revertants (15-40 per 0.1 mL cell sonicate) was even lower than control values (60-80 per 0.1 mL cell sonicate) and therefore considered negative.

The data suggest that neither cell line was capable of converting sodium azide to a mutagenic intermediate. In addition, both cell lines expressed the enzyme O-acetylserine (thio)-lyase which is responsible for the conversion of Sodium azide to azidoalanine, the putative mutagenic intermediate. Although mammalian cells possess the enzyme responsible for the conversion of sodium azide to azidoalanine, they appear incapable of converting Sodium azide into a mutagenic intermediate in appreciable quantities. Further, the data support the conclusion that sodium azide may be further modified in mammalian cells to an intermediate that is not genotoxic.